Potassium Ferrocyanide Used as an Anticaking Agent in Salt

Recently, there have been rumors circulating on the social media in mainland China claiming that potassium ferrocyanide in salt is hazardous to health. In fact, potassium ferrocyanide (INS no. 536) as well as sodium and calcium ferrocyanides (535 and 538) can be used as anticaking agents (substances that prevent powdered and granulated ingredients from lumping) in salt under Codex General Standard for Food Additives. Potassium, sodium and/or calcium ferrocyanides are permitted anticaking agents in many countries such as mainland China, the United States, Canada, European Union member countries, Australia and New Zealand, etc.

Some people may worry that toxic cyanide will be released when ferrocyanides are heated during cooking. However, because of the strong chemical bond between iron and the cyanide, usual cooking temperature is unable to break down ferrocyanide to cyanide. International food safety authorities have evaluated the safety of sodium/potassium/calcium ferrocyanides and concluded that there is no safety concern in current authorised use and use levels.